Oven construction



May '5, 1953 R. E. SHAW ETAL OVEN CONSTRUCTION 3 Sheets-Sheet 1 Filed Dec. 13, 1950 ROBER'T E sTEEv? SANDFORD C. PEEK,JR. BY

a f ZZTTOR Y May 5, 1953 s w ETAL 2,$37,754

OVEN cons'mucn ou Filed Dec. 13. 1950 3 Sheets-Sheet 2 I 6/ a 30 i] 23 i9 6 :h a: C I

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ATTORN y ,.1953 R. E. SHAW ETAL 2,637,754

OVEN cous'rauc'non Filed Dec. 13. 1950 3 Sheejcs-Sheet 3 S ROBERT E. SHAW s NDFORD C'PEEKHJR.

ATTO RN "UNITED STATES Patented May 5, 1953 Application-December. 13, 1950, Serial No. 2003322 "OFFICE 4 Claims. "1

This invention relates to heating apparatus and more particularly to an .oven for heating elongated vitreous articles such as linear'fluorescent tubes.

In the manufacture of circular fluorescent lamps from linear glass tubes, a proper heating of the tubes to permit satisfactory fabrication to a'circular configuration is a most important conslderation. The linear glass tubes should v be heated to a plastic condition and elongation thereof permitted to occur before fabrication to a circular configuration is attempted. On the other hand; care must be exercised to prevent the tubes from being heated to a point where control of their shape may be lost. Since the temperature range between sufficientheatingland excessive heating is notvery'great, considerable care must be exercised to heat the tubes to a degree of which falls within this range. The heating-problem' is rendered more difficult by the configuration' of the article being heated since it is a long slender tube, the length of which is many times greater than its diameter.

An object of our invention is to neatelongated Vitreous articles uniformly to a plastic condition,

The oven or our invention comprises a pair" of wall members, the inner faces'oi which. are provideo with a plurality of radiant heating elements; and a: convection heating e'lement'disposed at the base thereof. The flue gases from the convection heating element provides circulation of hot al'rabout" and along the lengthof". the art cles, thereby rendering the temperature of the articles substantially uniform along" their entire length.

A specific'embodiment oi the oven 01 our'inventlon ls'ill-ustrated in the accompanyin'gdrawings in which:

Figure l is a plan view partly in section of an apparatus for bendinq linear-fluorescent l'amos into circular shape, withwhich an oven embody ins our invention mav beemoloyed.

Figure 2 is a sectional elevational view taken along the line 2-2 ofFig'ure' 1' showing therelation of an even with respect to the turret-of the" mac ine,

Figure 3- is a longitudinal sectional viewof an embodiment of the oven of our invention.

Figure 4 is a transverse sectional view of the oven taken along the line '44 of' Ficure sandshowln the oven in the closed pos tion.

Figure 5' is a transverse sectional-view taken along the line 5'5 of Figure 3 and showing the oven in the open position.

Figure 6 is a lon itudinai sectional view of a convection heating element.

Referring'now' to the specific embodlmentof the invention illustrated in the drawings, particularly-Figures 1 and? thereof, a linear fluorescent lamp- I, held by a lamp'holder 2', and seated on a lamp support 3, is-carriedthrough'a muralityof work stations at which the lamp is heated andfinallyfabricated-to the desired configuration. Movement of the lamp I through a p1uralit y' or work stations ise'ffeeted one, rotatable turret type'machinein whicha plurality of lamp holders 2 and lam supports 3'? are mounted on a turret 4. The turret 4 comprises an upper ring plate'fi', about the periphery of which the plural ityof lamp holders 2' are mounted; a lower-ring plate' i, about the periphery'ofwhich the plurality of lamp supports-'3 are mounted; supporting-colurnn reopen-ding from the upper ringplatei, to the otherends of which" the lower ring plate? is attached; and a' spider 8 attached. to" the top of the upper ring platet. Rotation of the'turret 4' estalil. Stability imparted tothe turret d,

part cnlarlythe lower rin'e, plate :5 thereof, by rollers l5 mounted on the to s of posts it mounted on the base i l These rollers I 5 engage the inside faceof'the loo/er ring plate and aid in insuring true-circular-rotational movement-of the turret l'.

lteferring to Figures 1 and 2,he-ating of the linearfluorescent l'ampi is effected inseveral separate ovens 59 disposed at work stations adjacent to the periphery of the turret" 5'. Each oven 59 comprises open of semi-"circular members 68 and lii which define heating chamber, circular in cross-sectiom within which the lamp f is heated. oven su ported'frorn'a car-'- tween have not been shown since a suitable conventional arrangement may be employed. The piston rod 16 of the air cylinder 88 has a link guide 25 (Figures 4 and 5) attached to the outside end thereof. The link guide 25 has a pair of slots 26 cut therein, through which pins 2! upstanding on one end of levers E8 and 19 extend. The levers I8 and 19 are mounted intermediate their ends on the supporting shaft M, the other ends thereof being connected to oven members 68 and 6| respectively.

The carriage 89 is mounted on wheels 88 which ride on tracks 8| on carriage support 82. Reciprocating movement of the carriage 59 on the tracks 8| is effected by the reciprocating motion of air cylinder 83 mounted on the carriage 69. The source of air which actuates the air cylinder 83 and the connection therebetween have not their peripheries.

been shown since a suitable conventional arrangement may be employed. The outer end of the piston rod 84 of air cylinder 83 is fixed in a bracket 85 mounted on the carriagesupport 82. Thus when air cylinder 83 is actuated it moves along its fixed piston rod 84 and carries the carriage 69, on which it is mounted, with it.

Referring to Figures 2, 3, 4 and 5, each oven 59, as was mentioned above, comprises a pair of semi-circular members 80 and 8|. Each of the members 68 and 6| comprises a metal body member 28, to which the levers 18 and 19 are attached, an inside wall 29 of insulating material and an outside wall 38 of insulating material. The inside wall 29 of each of the members 6|] and 6| is provided with a plurality of separate radiant heating elements, such as electric heating elements 62 for example, disposed along the longitudinal axis thereof and connected to a source of electrical energy (not shown) Each of the members 68 and 8| is cut away at 63 and 64 to permit entrance of a portion of the lampholder 2 and the lamp support 3 when the carriage 69 moves the ovens 59 inwardly to envelop the lamps.

A convection heating element, such as conetype gas burner 65, is disposed inside the oven near the base thereof and is supported by a bracket 66 attached to the bottom of member 6| of oven 59. As may be seen in Figure 6, the burner 65 comprises a frame 81, a tunnel 3| mounted thereon, and a tip 32 seated in an aperture therefor in the frame 67 and disposed at the base of the tunnel 3|. A flexible hose 58, attached to the frame 61, is connected to a gas supply (not shown).

The combination of a plurality of separate radiant heating elements 62 spaced from one an- 4 other along the longitudinal axis of the oven 59 and a convection heating element 65 mounted near the base thereof and in register with but spaced from the bottom end of the lamp, provides a heating apparatus which heats the lamp uniformly to a plastic condition. A plurality of separate heating elements 62, each of which is provided with separate controls, enables adjustments to be made in the amount of heat being supplied at several areas along the longitudinal axis of the lamp. Disposition of the gas burner 65 near the lower end of the lamp l but spaced therefrom provides a source of hot gases which flow upwardly enveloping the lamp and thereby assisting indeveloping and maintaining uniform heating of the lamp.

In order to protect the electric heating elements 62 from pieces of a lamp which may accidentally break in the oven, a grill 33 is disposed between the heating elements 62 and the lamp I.

4 Although only one such grille 33 is. shown in Figure 3, additional grilles to protect the other heating elements 62 may be employed.

After the linear lamp has been heated in the last oven 59, it is moved to the lamp rolling station where it is formed into circular configuration by a roller 81. The lamp roller 81 comprises a pair of cooperating discs 88 and 89, which, when the adjacent faces thereof are brought into engagement with one another, define a mould 90 in Discs 88 and 89 are supported by a yoke 9| through shafts 92 and 93 respectively. The yoke 9| has a pair of bosses 98 formed in the sides thereof through which yokeguiding columns 99 mounted on pedestal I4, extend. Actuations of the yoke 9| to effect movement thereof up and down on the columns 99 is effected by an air cylinder 94 (connected to a source of air under pressure, not shown) mounted on pedestal M. The piston rod of the air cylinder 94 is connected to the yoke 9| through a rod 96, supported at its ends in a pair of rod supports 91 mounted on the sides of the yoke.

In their inoperative position, the discs 88 and 89, which comprise the lamp roller 81, normally are spaced from one another to permit movement of the lamp into operative position. Closing of the discs 88 and 89 to their operative position as shown in Figure 1 is effected by means of an air cylinder H23 (connected to a source of air under pressure, not shown) mounted on a bracket I84 on a side of the yoke 9|. The piston rod I of the air cylinder I83 is connected through a rack E86, a gear H37, and a suitable linkage mechanism to levers ill and H8. The levers II! and H8 are pivotally mounted intermediate their ends in the sides of yoke 9| and their other ends are pivotally connected to hubs |2| and I22 on discs 88 and 89. respectively.

Upon completion of the lamp rolling operation the lamp is then cooled at succeeding stations on the machine and finally removed.

That portion of the apparatus for fabricating the linear lamp to the desired configuration,

which is shown and described herein in connection with the oven of our invention, is the subject matter of the co-pending application of Sandford C. Peek, Jr., et al., entitled Apparatus for Bend-- ing Linear Glass Tubing, led of even date herewith.

- Whatwe claim is:

1. An oven for heating elongated vitreous articles comprising: a pair of wall members of insulating material disposed in a vertical plane; a plurality of separate radiant heating elements spaced from one another longitudinally along the longitudinal axis of said wall members and disposed adjacent to but spaced from the inner faces thereof; and a convection heating element disposed within the space defined by said wall members and located near the lower longitudinal ends thereof.

2. An oven for heating elongated vitreous articles comprising: a pair of wall members of insulating material disposed in a vertical plane; a plurality of separate electric heating elements spaced from one another longitudinally along the longitudinal axis of said wall members and disposed adjacent to but spaced from the inner faces thereof; and a gas burner disposed within the space defined by said wall members and located near the lower longitudinal ends thereof.

3. An oven for heating elongated vitreous articles comprising: a pair of wall members of insulating material disposed in a vertical plane; a plu-- rality of separate radiant heating elements spaced from one another longitudinally along the longitudinal axis of said wall members and disposed adjacent to but spaced from the inner faces thereof; a bracket attached to the bottom of one 5 of said wall members; and a gas burner mounted on said bracket and disposed within the space defined by said wall members.

4. An oven for heating elongated vitreous articles comprising: a pair of wall members of insulating material disposed in a vertical plane; a plurality of separate radiant heating elements spaced from one another longitudinally along the longitudinal axis of said wall members and disposed adjacent to but spaced from the inner faces thereof; a grille mounted on said wall members and disposed in front of and spaced from said heating elements; and a convection heating element disposed within the space defined by said wall members and located near the lower longitudinal ends thereof.

ROBERT E. SHAW. SANDFORD C. PEEK, JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 579,597 Moxham Mar. 30, 1897 919,843 Fish Apr. 27, 1909 1,218,582 Planstiehl Mar. 6, 1917 1,316,190 Sackerman Sept. 16, 1919 1,401,678 Darlington Dec. 27, 1921 1,420,181 Clark June 20, 1922 1,785,607 Willis Dec. 16, 1930 1,808,718 Bader June 2, 1931 1,915,949 Peterson June 27, 1933 2,057,431 Hobrock Oct. 13, 1936 

